Six inch barrles were built after 1978, I think. Sorry I can't be more help!
A few hundred to a thousand or more depending on configuration, age, condition and orginality.
colt diamond back is was made in 22lr & 38 special.with a ventilated rilb barrel. the colt trooper was chambered in 357mag. without a vent rib barrel.
No published sn data.
22LR
Aluminum receivers, steel barrel
you will have to have a gunsmith check it to be sure.
By a good gunsmith.
Have a Model M-846 (Montgomery Ward) semi auto with 18 inch barrel.
50-175 US Dollars
1956
The caliber should be marked on the barrel near the receiver. The Model 39 is a 22LR
Depending on condition, type of barrel, sights, etc, anywhere for $150-$300.